Plain end sewer pipe

ABSTRACT

Ceramic plain end sewer pipes having varying diameters, circumferences and degrees of roundness are provided adjacent each end with an external annular groove, which is on constant depth in relation to the outer surface of the pipe regardless of the out-of-roundness of the pipe. The cross section of the groove is constant for all pipes. The circumference root of all grooves is made constant by means of a plastic filler. The root diameter of the plastic-containing grooves varies with the diameter of the pipe and such grooves with the filler finish at a uniform depth around the pipe. O-rings of elastomeric material of uniform circumference and cross section fit the grooves and the adjacent pipe ends are forced into a flexible coupling sleeve, which conforms to out-of-roundness regardless of where it occurs in the adjacent pipe ends, so that the space between the pipes and the sleeve is uniform and is occupied by the O-rings, which are equally and uniformly compressed around the pipes to effect liquid-tight seals.

United States Patent [7 21 Inventor John D. Schmunk Findlay, Ohio [2]] Appl. No. 848,239 [22] Filed Aug. 7, 1969 w [23 Division of Ser. No. 680,078, Nov. 2, 1967, Rat-N9.- $2 2 [45] Patented Feb. 23, 1971 [73] Assignee The Hancock Brick and Tile Company Findlay, Ohio [54] PLAIN END SEWER PlPE 1 Claim, 3 Drawing Figs.

[52] U.S.Cl 138/109 [51] lnt.Cl Fl6l2l/02 [50] Field ofSearch 138/178, 109

[56] References Cited UNITED STATES PATENTS 2,401,554 6/1946 Davids 285/291 2,537,659 1/1951 Eisner et al. 285/230 Primary Examiner-William F. ODea Assistant ExaminerRichard J. Sher Attorney-Malcolm W. Fraser ABSTRACT: Ceramic plain end sewer pipes having varying diameters, circumferences and degrees of roundness are provided adjacent each end with an external annular groove, which is of constant depth in relation to the outer surface of the pipe regardless of the out-of-roundness of the pipe. The cross section of the groove is constant for all pipes. The circumference root of all grooves is made constant by means of a plastic filler. The root diameter of the plastic-containing grooves varies with the diameter of the pipe and such grooves with the tiller finish at a uniform depth around the pipe. 0- rings of elastomeric material of uniform circumference and cross section fit the grooves and the adjacent pipe ends are forced into a flexible coupling sleeve, which conforms to outof-roundness regardless of where it occurs in the adjacent pipe ends, so that the space between the pipes and the sleeve is uniform and is occupied by the O-rings, which are equally and uniformly compressed around the pipes to effect liquid-tight seals.

PATEN-TEDFEB23IB7I 3.565.117

' sum 1 BF 2 INVENTOR.

JOHN D. SCHMUNK VZQMOM HIS ATTORNEY PATENTED R 23 III 3.565.117 SHEET 2 m2 I FOLLOWS CONTOUR OF OUTER CONSTANT DEPTH GROOVE F SURFACE OF PIPE WALL' NOMINAL PIPE DIAMETER (IRREGULAR) VARIABLE DEPTH ROOT CIRCUMFERENCE SAME FOR ALL PIPES FILLER MATERIAL UNIFORM DEPTH INVENTOR.

JOHN D. SCHMUNK HIS ATTORNEY PLAIN END SEWER PIPE CROSS REFERENCE TO RELATED APPLICATION SUMMARY Difficulty is encountered in producing a liquid tight coupling for the adjacent ends of plain end ceramic pipes, such as sewer pipes, because of their lack of uniformity. After being dried from their plastic condition, there is considerable irregularity in their diameters and circumferences, although in their plastic state they were uniform. It is a desideratum to provide a novel pipe structure, which despite irregularities, can be coupled with similar pipes. economically and efficiently.

In accordance with this invention an external circumferential groove is formed in each pipe adjacent the end and, to make its root circumference constant, an amount of plastic fill is introduced sufficient to achieve'uniformity so that while conforming to irregularities in diameter, the root circumference of one groove is the samein'one pipe as in the other. This makes possible the use of the same O-ring for each groove and a uniform sleeve to containthe two pipe ends for compressing the O-rings for effecting the desired seal. Thus, it is possible to standardize on the O-rings and sleeves for the couplings, and this obviates the necessity of the extra expense of stocking several different sizes to cope with pipe variation.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is an exploded view partly in elevation and partly in section showing fragments of two plain end ceramic pipes having external O-ring receiving grooves containing a plastic filler and having root circumferences, and a coupling sleeve for receiving same;

FIG. 2 is a sectional elevation of the parts shown in FIG. 1 coupled together; and

FIG. 3 is a somewhat schematic transverse sectional view of an end portion of a pipe taken through the external groove and bearing informative legends.

DESCRIPTION OF PREFERRED EMBODIMENT In the drawings, A and B designate ceramic sewer pipes in which both the inside and outside diameters of pipe A exceed that. of pipe B. It is found in practice that although after extrusion these pipes are uniform, they change dimensions during the firing period and the variations may reside in varying degrees of roundness as well as differences in diameter and circumferences. These variations militate against the adoption of a standard liquid tight coupling of the usual form to fit the different sizes of pipe.

In this instance, there is formed in each end portion of each ceramic pipe, while in its plastic or semiplastic condition, an external circumferential groove, as indicated at 10, for pipe A and 11, for pipe 8. The grooves are shown'as being rectangular in cross section, but other shapes may be used. The root circumferences of the grooves and 11 are not the same in the two ceramic pipe ends. The root circumference of the groove 10 is greater than that of groove ll.'The depth of the groove 1 l is the same as that of groove 10. The depth of either groove is unifonn around the pipe even through the adjacent pipes vary in diameter, roundness and circumference.

Since the root circumference of the two grooves is not the same, manifestly the elastomeric O-rings 16 could not be equally compressed by the sleeve 12 to effect a liquid-tight seal for the pipe ends. Provision is made to cause each of the grooves 10 and 11 to have the same root circumference. For

this purpose of plastic tiller 17, such as a'quick-drying epoxy resin, is introduced, afler the pipes are fired, into each groove to which it adheres. It is predetermined, as indicated by arrowed line 18, ust what should be the constant circumference .for all pipe grooves. Then, by a simple rolling or cutting action, the proper groove is created in this plastic filler. Specifically, this groove root follows the configuration of the pipe in which it is being formed, so that its depth is constant in relation to the pipe outer surface. The forming action is controlled so that the root circumference is exactly as predetermined for all ceramic pipes.

With the field installation of the pipe, it will be understood that the O-rings 16, now inserted in the pipe A and the pipe B and resting in the grooves having identical root circumferences that, by forcing the two pipe ends into a flexible sleeve 12 which may be of semirigid polyethylene, the tapered end surfaces 15 gradually compress the O-rings equally until they are disposed in compressed condition in their grooves and against the cylindrical surfaces 14, whereupon an effective liquid-tight seal is secured. As an assembled coupling joint the sleeve 12, being flexible, is equidistant from the pipe outer wall entirely around both ends of the sleeve even though either or both of the pipes have irregular diameters.

Reference is made to FIG. 3 for purpose of clarity where C represents a pipe cross section in which the arrowed line D represents the nominal inside diameter, which usually is irregular. E represents the outer surfaceof the pipe, which is out-of-round and F designates the O-ring receiving groove, which is of constant depth and follows the contour of the outer surface of the pipe wall. Within the groove F is the filler material G, which is of variable depth so as to make the root circumference of the groove F constant for all pipes. In view of this circumstance, the same O-ring may be used for all pipes.

Numerous changes in details of construction and choice of materials may be effected without departing from the spirit of the invention.

lclaim:

1. A fired plain-end ceramic pipe in which the diameter, circumference, and the degree of out-of-roundness differ from that of another similar pipe due to the tire hardening of said pipes, said ceramic pipe having an external groove, adjacent each end, of constant depth from the outer surface of the pipe wall, filler material disposed completely in said grooves of a thickness sufficient to make the modified grooves of a circumference equal to other similarly modified grooves in a similar pipe while still conforming to the contour of the outer pipe wall, thereby to enable the coupling of said pipe to a similar pipe by applying the same sized O-rings in the grooves of each pipe and enclosingthe pipe ends in a tight fitting sleeve. 

1. A fired plain-end ceramic pipe in which the diameter, circumference, and the degree of out-of-roundness differ from that of another similar pipe due to the fire hardening of said pipes, said ceramic pipe having an external groove, adjacent each end, of constant depth from the outer surface of the pipe wall, filler material disposed completely in said grooves of a thickness sufficient to make the modified grooves of a circumference equal to other similarly modified grooves in a similar pipe while still conforming to the contour of the outer pipe wall, thereby to enable the coupling of said pipe to a similar pipe by applying the same sized O-rings in the grooves of each pipe and enclosing the pipe ends In a tight fitting sleeve. 